Patent GB-335702-A (GB)
Title: Improvements in railway signal control apparatus
IPC: B61L23/10
Filed: 1929-08-29
Abstract: 335,702. Tyer & Co., Ltd., and punter, J. W. Aug. 29, 1929. Signalling-instruments; combined electrical and mechanical systems, non-automatic; interlocking. -In a block signalling-system in which each station instrument is provided with a receiving and dispatching commutator, each commutator is normally locked and only released on receipt of a current from the other station; the starting signal at the despatching end can only be released when the despatching commutator has been released. The Figure shows only the circuits for the despatching commutator 3 at station A and the receiving commutator 11<b> at station B, the contact segments being shown in developed view. The commutators can only be moved in one direction and are normally locked by gravity catches 68, 45 pivoted on armatures 4, 12b of electromagnets 5, 13<b> but after momentary energization of the magnets the catches rest on top of the - commutator shoulders 69. 46 so that the commutators can be moved through a step of 120‹. Actuation of a signalling key 1 at the despatching station A energizes a polarized relay 7b at the receiving station B, the circuit being :-battery 26, fingers 16, 17, earth, wire 28 at station B, polarized relay 7b, wire 29, fingers 22<b>, 21b, wire 30, upper contact 31 of key 1<b>, line wire 32, lower contact 33 of key 1, wire 34, fingers 19, 18, back to battery 26. The relay armature closes at its contacts 40, 41 the circuit of the release magnet 13b of the receiving commutator 11<b> which is then turned 120‹ to the " line clear " position and a return signal current is sent from the battery 26<b> over line wire 32 to energize a polarized relay 7 at station A normally, this last circuit being over fingers 16<b>, 19<b>, wire 49, lower contact 50 of the signalling key 1<b>, line wire 32, upper contact 51 of key 1, wire 52, fingers 21, 22, wire 53, earth, and back to battery 26<b> over fingers 17b, 18b. The release magnet 5 of the despatching commutator 3 is energized over the normal relay contacts 58, 59 whereupon the despatching commutator 3 can be moved 120‹ to the " line clear " position in which position the energization of a starting signal release lock 9 is effected over fingers 64, 65 from a battery 70. A line current is again sent to station B to permit the receiving commutator 11<b> to be turned to the " train on line " position at 240‹. As it passes the 180‹ position a return current is sent automatically to station A to energize the polarized relay 7 reversely so that the release magnet 5 of the despatching commutator is energized from the battery 56 over reverse contacts 58, 59<1> and fingers 63, 62 and the commutator 3 can be set to " train on line." The circuit at the 180‹ position of the receiving commutator 11<b> is battery 26b, fingers 16b, 17<b>, earth, relay 7, wire 53, fingers 22, 21, wire 52, upper contact 51 of signalling key 1, line wire 32, upper contact 31 of key 1<b>, wire 30, fingers 21<b>, 20b, 19<b>, 18b, to battery 26b. The arrival of the train at station B depresses a treadle 15 to close a circuit over fingers 24<b>, 25b for the release magnet 13<b> of the receiving commutator 11<b> which is then turned to " line normal " and a line current sent as before to reversely energize the polarized relay 7 at station A so that the release magnet 5 is energized over reverse contacts 58, 59<1> and fingers 63, 62 to permit the despatching commutator to be restored to " line normal."